A2C w/o loss function

main.py

@@ -11,21 +11,70 @@ from tqdm import tqdm
 import gymnasium as gym
 from pettingzoo.mpe import simple_crypto_v3
 
-class A2C():
-    def __init__(self):
-        pass
+class A2C(nn.Module):
+    def __init__(
+        self,
+        n_features: int,
+        n_actions: int,
+        device: torch.device,
+        critic_lr: float,
+        actor_lr: float
+        ) -> None:
+        
+        super().__init__()
+        self.device = device
 
-    def forward(self):
-        pass
+        critic_layers = [
+            nn.Linear(n_features, 8),
+            nn.ReLU(),
+            nn.Linear(8, 8),
+            nn.ReLU(),
+            nn.Linear(8, 1)
+        ]
 
-    def select_action(self):
-        pass
+        actor_layers = [
+            nn.Linear(n_features, 8),
+            nn.ReLU(),
+            nn.Linear(8, 8),
+            nn.ReLU(),
+            nn.Linear(8, n_actions),
+            nn.Softmax()
+        ]
+
+        self.critic = nn.Sequential(*critic_layers).to(self.device)
+        self.actor = nn.Sequential(*actor_layers).to(self.device)
+
+        self.critic_optim = optim.RMSprop(self.critic.parameters(), lr=critic_lr)
+        self.actor_optim = optim.RMSprop(self.actor.parameters(), lr=actor_lr)
+
+    def forward(self, x: np.array) -> tuple[torch.tensor, torch.tensor]:
+        x = torch.Tensor(x).to(self.device)
+        state_values = self.critic(x)
+        action_logits_vec = self.actor(x)
+        return (state_values, action_logits_vec)
+
+    def select_action(self, x: np.array) -> tuple[torch.tensor, torch.tensor, torch.tensor, torch.tensor]:
+        
+        state_values, action_logits = self.forward(x)
+        action_pd = torch.distributions.Categorical(
+            logits=action_logits
+        )
+        actions = action_pd.sample()
+        action_log_probs = action_pd.log_prob(actions)
+        entropy = action_pd.entropy()
+        return actions, action_log_probs, state_values, entropy
 
     def get_losses(self):
         pass
 
-    def update_params(self):
-        pass
+    def update_params(self, critic_loss: torch.tensor, actor_loss: torch.tensor) -> None:
+        self.critic_optim.zero_grad()
+        critic_loss.backward()
+        self.critic_optim.step()
+
+        self.actor_optim.zero_grad()
+        actor_loss.backward()
+        self.actor_optim.step()
 
 #environment hyperparams
 n_episodes = 10
@@ -56,5 +105,6 @@ while env.agents:
     
     actions = {agent: env.action_space(agent).sample() for agent in env.agents}
     observations, rewards, terminations, truncations, infos = env.step(actions)
+    print(observations)
 
 env.close()